The Photorefractive Effect in Ferroelectrics

Abstract

From the phenomenological (Sect.2.3) and microscopic (Chap.3) discussion of the influence of nonequilibrium carriers on the ferroelectric properties of crystals, we deduce that illumination must influence the spontaneous polarization P₀ and, in turn, lead to the corresponding change in birefringence (the Pockels effect). The formation of strong fields $\tilde E$ in a high-resistance ferroelectric as a result of an anomalous photovoltaic effect (AP effect) may also cause a change in birefringence. Therefore the influence f intense illumination on birefringence in ferroelectris, which was discovered relatively recently [7.1,2], can be considered as a genuine photoferroelectric phenomenon.